Trend analysis of flood data in Australia : a case study for Victoria

![CDATA[The possible impact of climate change on water resources management has received a great deal of attention from scientists all over the world. It has been noted that climate change will have a significant impact on various aspects of hydrologic cycle such as rainfall and floods. Due to climate change, the flood data can no longer be assumed stationary. Previous studies have shown that about 15% of Australian stream gauging stations show trends in annual maximum flood data, mostly downward in the south & south-east regions and upward in the northern region. These studies were based on the flood data till 2005 as part of Australian Rainfall and Runoff Revision Project 5. In this study, an updated database has been prepared for the annual maximum floods covering till year 2011 for the state of Victoria. This updated database is then used in this paper to identify trends in annual maximum flood series data using Mann-Kendall test. It has been found that 26% of the selected stations exhibit a downward trend at 5% level of significance, and none show an upward trend. The trend analysis was also repeated for 10% and 1% significance levels as well. Here, 60 stations show trends (i.e. 39% of the stations) at 10% level of significance and 14 stations show trends (i.e. 9% of the stations) at 1% level of significance. In all cases, the demonstrated trends are much higher than that would have been shown by mere sampling variability. Furthermore, no noticeable relationship between trends and catchment areas is identified. The reason behind these trends is being examined, and will be reported in future publications.]]